Project Summary/Abstract Early math skills are key to children?s long-term academic and career success, but many children from disadvantaged backgrounds start their formal schooling lagging behind their peers in early math skills development. Beyond family disadvantage, between 3 ? 6% of the population has a diagnosed math learning disability, which limits their ability to benefit from early math interventions. Many unanswered questions remain around which particular skill sets are key to target in early math interventions, including ongoing debates about the role of children?s non-symbolic numerical magnitude comparison skills as an intervention target. Researchers have also identified a close link between children?s executive functioning skills and their early math achievement, but most studies have failed to find an executive functioning skills intervention that specifically transfers to children?s math achievement. This proposal will test a novel account of children?s early math skills development, the Flexible Attention to Magnitudes account. This account argues that one key difficulty young children have in early math activities that is not addressed by current interventions is the ability to disentangle numerical and spatial magnitude cues (e.g., comparing 3 large elephants to 6 small mice) and to attend flexibly to both cues in math problem solving. This ability may explain children?s difficulties with particular types of non-symbolic numerical magnitude comparison tasks and may help preschool-aged children develop both their executive functioning skills and their math skills. The first goal of this project is to develop an assessment of children?s flexible attention to numerical and spatial magnitudes. Using this assessment, the second goal is to assess the associations between children?s performance on this assessment and their executive functioning and math skills (including overall math achievement as well as specific early math skills such as non-symbolic numerical magnitude processing). The third goal is to conduct a clinical trial of the malleability of children?s flexible attention to magnitudes. The goals of this proposal are consistent with NIH?s mission to provide fundamental knowledge about the human behavior, specifically in the area of early math cognition. This proposal is also closely aligned with NIH?s mission to apply basic research knowledge to enhance health and reduce disability, as the improvement of young children?s early math skills can have lasting impacts on their later academic and career success, leading to better health outcomes. Further, this proposal involves children from disadvantaged backgrounds who are at-risk for math learning difficulties, and the outcomes of this project may be used to address specific needs of children with math learning disabilities.